To comply with the 3GPP2 CDMA packet data services standard “3GPP2 C.S0017-012-A v1.0: Packet data Service Options for Spread Spectrum Systems: Service Options 33 and 66” (also known as TIA-707.12-B), a mobile station with a dormant packet data session is required to “reconnect” its packet data service whenever it detects a change in System ID (SID), Network ID (NID) or Packet Zone ID (PZID) parameters associated with the wireless network. The reconnect process is required to maintain PPP (point-to-point protocol) connectivity in case the wireless network needs to move the so-called “R-P” interface (also known as A10 and A11) between the Radio Access Network (RAN) and the Packet data Servicing Node (PDSN) associated with the packet data service or in some cases needs to assign a new IP address to the mobile station. The reconnect process requires the mobile station to send an origination message with Packet data Service option and Packet data Ready to Send (DRS) bit. The wireless network may assign a traffic channel to the mobile station during the reconnect process.
A feature called “packet zone hysteresis” is included in 3GPP2 C.S0017-012-A v1.0 in order to minimize the number of packet data reconnects when the mobile station moves back and forth between two systems while in a dormant state (such as SID/NID/PZID boundary). To implement the hysteresis feature, a mobile station keeps track of visited systems in a list which is called “Packet Zone List” in 3GPP2 C.S0017-012-A—each entry except the most recently added entry has a hysteresis timer. If a mobile station revisits a system whose hysteresis timer has not expired yet and it does not have any packet data to send, then it refrains from reconnecting its packet data service until the hysteresis timer has expired.